Harold Tobin

Research

Nearly all the plate tectonic "action" on Earth takes place at the edges, where plates meet at major faults. These plate boundary faults are sites of active deformation, earthquakes, and are the source of tsunami, but we still don't understand many fundamental things about how they work.

I am interested in the internal properties of active faults at the Earth's plate boundaries - for example, subduction zones in the Pacific Ocean and the San Andreas fault in California. In my research, I combine direct sampling of faults deep beneath the surface of the Earth - through drilling at sea and on land - with detailed 3D seismic reflection imaging of the fault architecture and properties. Laboratory experiments on the mechanics and physics of the fault rocks completes the link among these different ways of "seeing" into active fault zones.

Some of my active research projects are:

NanTroSEIZE

My major effort is as co-Chief Project Scientist of the Nankai Trough Seismogenic Zone Experiment (NanTroSEIZE), a multi-year project to drill into and place instruments in the subduction zone plate boundary faults off the coast of Japan. NanTroSEIZE is part of IODP, the Integrated Ocean Drilling Program, and is the most ambitious and complex scientific drilling program ever undertaken.

A short video introducing the NanTroSEIZE project and my research (Deep-sea drilling in the Nankai Trough):

Also, here is a link for a different video, a 5-minute segment about my research from a Discovery Channel special called "Exploring Time."

San Andreas Fault Observatory at Depth (SAFOD)

I am also involved in the San Andreas Fault Observatory at Depth (SAFOD) project, a study of the internal workings of the San Andreas through land-based drilling. My students and I are tackling laboratory experiments on friction and elastic properties of rocks from SAFOD cores to better understand the make-up of the fault zone.